1. Field of the Invention
The present invention relates to a behind-stop type photographic camera lens system designed for an aperture ratio of F/2.8, field angle of 60.degree. and a short total length.
2. Description of the Prior Art
Almost all the conventional behind-stop type lens systems for 35 mm photographic cameras had relatively narrow field angles or, when designed for relatively wide field angles, large telephoto ratios (ratio of distance measured from the front side to the back focal point relative to focal length of lens systems), thereby prolonging their total lengths. When it is attempted to design a behind-stop type photographic camera lens system so as to have a small telephoto ratio and a wide field angle, on the other hand, marginal rays become insufficient. If lens diameter is increased to obtain sufficient marginal rays, it will be impossible to design a compact lens system. Japanese Published Examined Patent Application No. 15462/1966 and No. 26670/1971 have already disclosed photographic camera lens systems which are similar to Tesser type and comprise two positive lens components, a negative lens component and a positive cemented lens component. In these lens systems, however, the cemented surface in said positive cemented component is convex on the object side, thereby unavoidably aggravating astigmatism.